EB1 peptide (Penetrating analog) is an endosomolytic agent and siRNA delivery agent. EB1 peptide forms an amphipathic alpha helix upon protonation in early-late endosomes, drives endosomal membrane permeabilization, and enables endocytosed siRNA escape into the cytosol. EB1 peptide facilitates biologically active siRNA cellular uptake and targeted gene silencing. EB1 peptide forms complexes with siRNA. EB1 peptide can be used for drug delivery research[1].